When it comes to ranking, of course, it’s not quite as simplistic as that (it rarely is!). As well as the bid an advertiser places on a keyword, the search engine will take a number of other factors into account. In the case of Google AdWords, this is known as Quality Score (QS). Quality Score is applied on a keyword, adgroup and account level. It is important that your entire account has a good Quality Score, as it affects ranking and cost per click.